1. Field of the Invention
This invention relates to evaporative cooling systems and, more particularly, to evaporative cooling systems which employ a two-speed motor and a pump for pumping water for saturating pads through which air is forced by a fan or blower powered by the two-speed motor, and with thermostatic control to actuate the apparatus.
2. Description of the Prior Art
In geographical areas where humidity is low during hot weather, evaporative cooling systems are used to lower the temperature of the air by increasing the humidity of the air. The hot, dry air is forced by a blower or fan through pads saturated with water. A water pump is used to lift water from a reservoir to the tops of the pads. The water then flows downwardly, by gravity, through the pads, soaking them, and back to the reservoir. The flow of air through the water-saturated or soaked pads causes the water to evaporate, and the heat of vaporization given off by the air as the water is evaporated results in a decrease in the temperature of the air. As relative humidity increases, the efficiency of such evaporative cooling system decreases. However, where relative humidity is low, evaporative cooling systems function quite satisfactorily for reducing the temperature of the air.
For enhancing the workability or efficiency of evaporative coolers, several options are available. Each of the options requires a separate control. With the apparatus of the present invention, the options are integrated into a single control.
A two speed motor may be used with an evaporative cooler to provide two different air flow rates. The amount of cooling may thus be varied to suit the circumstances of any particular situation.
Another option with respect to evaporative cooling systems is the control of the water pump separate from the blower. For presoaking the cooler pads, the pump should be on before the blower is turned on. This presoaking allows the evaporative cooler to be functionally effective as soon as the blower is turned on. If the pump and blower are turned on at the same time, there is a time lag in the operational effectiveness of the cooler because of the extra time required to fully soak or saturate the pads. The moving air may evaporate the water from the pads almost as fast as the water is pumped in, depending on the circumstances of temperature, humidity, etc., decreasing the effectiveness of the cooler. Accordingly, there is a time lag between the turning on of both blower and pump and the full effectiveness of the system. This time lag is greater than the time required to presoak the pads by turning the pump on before turning on the blower.
Two separate switches are required to control the pump and the blower separately. In the prior art, these switches are manually operated in two separate operations.
There is also another advantage of being able to control the blower or fan separately from the water pump. When the water is off, no water is flowing to the pads and the flow of air through the pads is therefore direct, without the benefit of cooling by the evaporation of the water. There are times when merely a flow of air is sufficient for cooling purposes and accordingly the pump is not required.
The prior art evaporative cooling systems generally comprise two separate switches, a switch for controlling the fan or blower, and a separate switch for controlling the operation of the pump, if such capability or option is used. If not, then a single switch is used to control both the blower and the pump in parallel. There have been individual situations where a thermostat has been used to control the operation of an evaporative cooling system, but such thermostatic control has been of a relatively elemental level, comprising only the actuation of a single speed blower motor by itself, or the actuation of a blower motor and a water pump, tied together. The option of selecting a particular speed of a motor, or a particular speed with or without an accompanying water pump, has not heretofore been accomplished by a single control.